WhatsApp has added a “Share to Facebook” function.
The feature allows you to long press on a message and share the message to Facebook.
The share to Facebook feature will probably become more useful with time as Facebook (the parent company of WhatsApp and Instagram as well) launches Portal.
The probability that users will be able to add a story to their WhatsApp, Facebook and Instagram by adding to a story to one of these services is pretty high.
Portal seems like an attempt to integrate these 3 services such that targeted advertising follows you whether you’re using FB, IG or WhatsApp.
Keep in mind ads will be coming to WhatsApp next year, so it makes sense for Facebook to want those adverts coming to your personal messaging service to be as accurate as possible.